The curtain opens on the pomp and pageantry of a truly Gilded Age: Imperial Russia, circa 1874.

Our prima donna is Anna Karenina (Keira Knightley), a beautiful, passionate and privileged woman wed to a stern, principled government official (Jude Law). Like that of her husband, her reputation in aristocratic circles is spotless, her conduct beyond reproach.

That all changes when Anna travels by train from St. Petersburg to Moscow to visit her brother, civil servant Stiva Oblonsky (Matthew Macfayden), whose dalliances with the family governess have landed him in hot water with his wife, Dolly (Kelly Macdonald). On board, she bumps into Countess Vronskaya (Olivia Williams), whose affaires de coeur are legendary in upper-crust society, and her equally promiscuous son, dashing cavalry officer Count Vronsky (Aaron Taylor-Johnson).

Vronsky may be technically off-limits — after all, he’s romantically linked to Dolly’s 18-year-old sister, Kitty (Alicia Vikander) — but the spark that flies between them is unmistakable.

Those feelings are later fanned into flame at a ball when Vronsky takes Anna in his arms, ignoring Kitty — and the hushed reactions of the shocked onlookers — entirely.

Anna is clearly disturbed by such a public indiscretion, but she can’t deny the desperate attraction she feels. “If you have any thought for me, you will give me back my peace,” she pleads.

“There can be no peace for us,” Vronsky replies, “only misery, and the greatest happiness.”

His words prove prophetic. As the adulterers embark on a passionate love affair, Anna finds herself the subject of ruthless gossip, scorned by her humiliated husband and shunned by all but her closest friends. Whispers gradually build to roars.

Anna and Vronsky’s torrid tryst stands in sharp contrast with the slow, sweet courtship of Kitty by Oblonsky’s landowner friend Levin (Domhnall Gleeson), who’s more comfortable swinging a scythe in a wheat field than holding court with his fellow aristocrats. Theirs is the film’s only unsullied relationship, as pure as Anna’s is poisonous.

In the face of certain ruin, Anna must decide whether she’s willing to sacrifice everything — her adorable young son, her social status, even her life — for the sake of love.

Oscar nominee Keira Knightley, who previously worked with director Joe Wright in “Pride & Prejudice” and “Atonement,” is electrifying here as the title tragic heroine — torn between passion and devotion, wracked with jealousy and consumed with fear.

Whether shrouded by veils or festooned with feathers, she suffers in silence and magnificent rages. (The camera clearly loves doe-eyed, swan-necked Knightly; her elegant profile appears on screen so many times it could be considered a visual motif.)

She finds a charming foil in Aaron Taylor-Johnson, a curly-haired up-and-comer whose credits include “Kick-Ass,” “Nowhere Boy” and “Savages.” Here he provides his most compelling performance yet.

Wright provides a suitably splendid setting for his star-packed cast. Working with cinematographer Seamus McGarvey and production designer Sarah Greenwood, he creates an atmosphere of art and artifice — part grand theater, part cinematic marvel — that turns private moments into public entertainment.

There’s a sense of the characters being constantly on display. Only off-stage — away from the prying eyes and judgmental hearts of snobby society matrons– can the characters comfortably express themselves.

Although “Anna Karenina” is unquestionably lush — Jacqueline Durran’s gorgeous costumes and Dario Marianelli’s swooningly romantic score are practically worth the price of admission alone — all of those artistic trappings occasionally obscure the film’s bigger themes, including faith, fate, morality, inequality and, of course, love in its many forms. I can’t imagine “Anna Karenina” author Leo Tolstoy, that austere old saint, would have been very happy about that.

But does it matter Tolstoy would have thought?

This is a production in the truest sense of the word, an astounding achievement in filmmaking. To view “Anna Karenina” as anything else is to ignore its deep, abiding beauty.